In the country or the plot is always required to have a supply of water for domestic needs. Keep the tank in the shower or reservoir for watering the plants and filled to the required level will help you simple electronic machine.
Consider the operation of the device over the concept. If water is not available or its level reaches sensor E2, when you turn on the switch Q1, the transistor VT1 is closed, relay K1 is de-energized, and through its NC contact pair K1.2 AC voltage goes to the pump motor, pumping water into the tank. Once the water level reaches sensor E2, the base circuit of the transistor closes, and it opens. Will trigger the relay and opens the contact K1.2, thereby breaking the supply circuit of the motor of the water pump. At the same time contact pair K1.1 connects to the base VT1 sensor E3, providing the open state of the semiconductor device until then, until the water level (if used) will not fall below the sensor E3 (or E1) and the cycle of water injection again. The diode VD2 eliminates inductive interference that occurs when the relay K1. When you turn off Q1, the regulator takes out the pump pumping the water stop.
Schematic diagram of the regulator.
Schematic diagram of the controller.
The device used electromagnetic relays brand PE-22УЗ with the weakened spring of the armature; the coil resistance is 90 Ohms, trigger current of 90 mA. Will also fit any other relay with a sufficiently powerful contactors actuated at a voltage of 12-15 V, for example, RES-8 (passport RS4.590.064).
Transistor П213Б permissible to replace П217, KT814 with any alphabetic index. The radiator for it is made of a piece of aluminum angle with a flange width of 40 mm.
Instead of a block КЦ402Г you can collect the rectifier bridge circuit of diodes with average rectified current of 0.2—0.5 And, for example series D226, КД105. Also indicated on the diagram of the device Д9Б applicable any diodes D9, D226. Oxide capacitor C1 with a capacity of 50-500 microfarads and a working voltage greater than 15 V — type K50-6.
Trimmer resistor — SPZ-9 or SP2-3b. Adjusting it to achieve clear operation of the machine, as water in different areas has a different conductivity. Suitable fixed resistor 1 is 2 ohms, a capacity of at least 0.5 watts.
Transformer T1 is a low power, secondary winding voltage of 12-15 V. Can be used, for example, TCE-110Л2 from TVs or wound yourself on the yoke SLM 16X20. The primary winding comprises 2400 turns of wire PEV-2 0,12, secondary — 136 turns of PEV-2 of 0.28.
Switch Q1, the switch TP1 — 2, or any two-pole switch for switching current of at least 2 A.
The regulator is installed in a dry, protected against atmospheric exposure location (indoor), preferably closer to the input power wiring.
The sensors E1—E3 are made of stainless steel welding electrodes Ø 4 mm. Length of E2 is less than the rest of the sensors 40-50 mm. They are secured on epoxy glue in a plastic bracket with two M4 screws fixed to the internal wall of the tank. The tail of the sensors in the places of fastening the wires must be sealed with epoxy or sealant.
Circuit Board with the layout of the elements.
Circuit Board with the layout of the elements.
If the water tank is made of metal, you can do without the sensor E1. In this case, the conductor extending from the resistor R1, is connected to the tank body using screw and washer.
Node fastening of the sensors.
The knot of fastening sensors:
1 — M4 screw, 2 — sensors E1 and E3, 3 — tank wall, 4 — bracket 5 — sensor E2.
The device is easy to turn in the alarm device of water level. To do this, instead of a relay K1 includes a filament lamp voltage 12 V Lamp will glow when the water level reaches sensor E2. Sensor E3 in this case is not necessary.

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